This invention relates to systems for continuous fuel injection into the intake line of an internal combustion engine and, more particularly, to a new and improved continuous fuel injection system providing better acceleration response.
In certain conventional fuel injection systems as described, for example, in DE-OS No. 29 00 691 and DE-OS No. 29 00 636, some air is withdrawn from the air intake line and mixed with the fuel which is supplied by a metering device as a function of the operating state of the internal combustion engine. The withdrawal of air and the metering of fuel are effected independently of each other and the fuel and air are combined into a fuel-air mixture just ahead of the distributor which supplies the mixture to the individual cylinders of the internal combustion engine. With this arrangement, a mixture of air and fuel is delivered through the injection points into the intake manifold pipes of the internal combustion engine in a constant manner. Even with a full load on the internal combustion engine, the fuel-air mixture is properly prepared before it is injected. Moreover, because the fuel is injected into the withdrawn air just before the fuel-air mixture is supplied to the manifold close to the engine, there is a substantial reduction in the response time of the fuel injection device when the operating state of the internal combustion engine changes. It has been found that such systems work satisfactorily. In spite of the relatively short response time of fuel injection systems which are electronically operated, however, difficulties arise at times, especially when the internal combustion engine is accelerated abruptly from low partial-load ranges. At such sudden load increases on the internal combustion engine, the fuel quantity apportioned by the metering device frequently is not sufficient to produce the desired acceleration of the internal combustion engine.
Therefore, it is an object of this invention to provide an improved fuel injection system of a simple and inexpensive construction wherein a sufficient fuel supply is ensured, even when there are sudden load increases, without requiring special acceleration enrichment arrangements.